Foreign object detection device

Abstract

In a foreign object detection device that detects foreign objects located in the lower rear part of a vehicle seat, the irreversible deformation of the pressure sensor is suppressed. [Solution] The foreign object detection device 7, positioned at the rear lower part of the vehicle seat 1 and detecting foreign objects present at the bottom of the vehicle seat 1, comprises a pressure sensor 21 and a stopper 25. The pressure sensor 21 detects the pressing force exerted by foreign objects located at the rear lower part of the vehicle seat 1. The stopper 25 suppresses deformation of the pressure sensor 21 in the direction of pressing.

Description

Technical Field

[0001] The present disclosure relates to a foreign object detection device that detects foreign objects present in the lower rear part of a vehicle seat.

Background Art

[0002] For example, in a device such as an automatic sliding door of a vehicle, a technique for detecting the pinching of a foreign object is known. For example, in Patent Document 1 below, in an automatic sliding door of a vehicle, when a foreign object is pinched between the door and the vehicle body, a pressure sensor is pressed and deformed, and the wiring inside the pressure sensor is short-circuited to detect the foreign object. A technique has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if the pressure sensor is pressed excessively, the pressure sensor may be irreversibly deformed and lose its function as a pressure sensor. In particular, when the pressure sensor is left at a high temperature for a long time, the pressure sensor is likely to be irreversibly deformed.

[0005] One aspect of the present disclosure is to be able to suppress irreversible deformation of a pressure sensor in a foreign object detection device that detects foreign objects present in the lower rear part of a vehicle seat.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a foreign object detection device (7) positioned at the rear lower part of a vehicle seat (1) for detecting foreign objects present at the lower part of the vehicle seat (1), comprising a pressure sensor (21) and a stopper (25). The pressure sensor (21) detects the pressing force exerted by a foreign object located at the rear lower part of the vehicle seat (1). The stopper (25) suppresses deformation of the pressure sensor (21) in the direction of pressing.

[0007] With this configuration, the stopper (25) suppresses excessive deformation of the pressure sensor (21) in the pressing direction, thereby preventing irreversible deformation of the pressure sensor (21). One aspect of the present disclosure may further include a pressure sensor mounting plate (23) and a pressing plate (27). The pressure sensor mounting plate (23) is a plate-shaped member extending in the width direction of the vehicle seat (1) to which a pressure sensor (21) is attached. The pressing plate (27) is a plate-shaped member extending in the width direction of the vehicle seat (1) and can press the pressure sensor by moving closer to and further away from the pressure sensor mounting plate (23) in response to the pressing force of a foreign object. The stopper (25) may be configured to protrude from at least one of the pressure sensor mounting plate (23) and the pressing plate (27) in the space between the pressure sensor mounting plate (23) and the pressing plate (27).

[0008] With this configuration, the pressing plate (27) extending in the width direction presses against the pressure sensor (21), so that the pressure sensor (21) can detect foreign objects over a wide area in the width direction without having to arrange the pressure sensor (21) over a wide area in the width direction. In addition, since the stopper (25) is configured to suppress excessive movement of the pressing plate (27), irreversible deformation of the pressure sensor (21) can be suppressed.

[0009] In one aspect of this disclosure, the stopper (25) may be arranged along the outer circumference of the pressure sensor (21). With this configuration, deformation of the pressure sensor (21) can be suppressed more effectively compared to a configuration in which the stopper (25) does not follow the outer circumference of the pressure sensor (21). [Brief explanation of the drawing]

[0010] [Figure 1] This is a side view of a vehicle seat equipped with a foreign object detection device. [Figure 2] This is a perspective view showing a foreign object detection device according to the first embodiment. [Figure 3] This is a front view showing a foreign object detection device according to the first embodiment. [Figure 4] This is a side cross-sectional view showing the movement of the foreign object detection device according to the first embodiment. [Figure 5] This is a perspective view showing a foreign object detection device according to the second embodiment. [Figure 6] This is a side cross-sectional view showing the movement of the foreign object detection device according to the second embodiment. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. The following "Embodiments of the Invention" are examples of embodiments that fall within the technical scope of this disclosure. In other words, the features defining the invention as described in the claims are not limited to the specific configurations and structures shown in the embodiments below.

[0012] [1. First Embodiment] [1-1. Structure] The vehicle seat 1 shown in Figure 1 is a seat installed in a vehicle such as an automobile. The vehicle seat 1 can be installed in any vehicle, such as an automobile, railway car, ship, and aircraft. The vehicle seat 1 has a function to detect foreign objects present beneath the vehicle seat 1 using a foreign object detection device 7, which will be described later. The vehicle seat 1 is configured to be displaceable in the vertical direction of the seat. The vehicle seat 1 comprises a seat cushion 3, a cushion frame 5, a lifting mechanism (not shown), and a foreign object detection device 7. The vehicle seat 1 may further include a seat back 4.

[0013] The seat cushion 3 is the part that supports the seated person's buttocks. The seat back 4 is the part that supports the seated person's back. The seat back 4 is positioned to extend upward from the rear end of the seat cushion 3. The cushion frame 5 is a component that forms the skeleton of the seat cushion 3 and is positioned inside the seat cushion 3. The cushion frame 5 comprises a pair of side frames (not shown), a pair of connecting rods 13, and an S-shaped spring 15.

[0014] The side frames are members provided at both ends of the seat cushion 3 in the seat width direction and extending in the seat front-rear direction. The connecting rods 13 are members provided at both ends of the seat cushion 3 in the seat front-rear direction and extending in the seat width direction. The connecting rods 13 are connected to a pair of side frames at the front and rear of the side frames. The S-shaped springs 15 are members arranged to connect the pair of connecting rods 13.

[0015] The lifting mechanism is a mechanism that displaces the vehicle seat 1 in the vertical direction. A well-known lifting mechanism used in electric power seats can be used for the lifting mechanism. The vehicle seat 1 is attached to the floor surface 30 via a mounting part (not shown), and the lifting mechanism is positioned at this mounting part.

[0016] The foreign object detection device 7 shown in Figures 2 and 3 is a device for detecting foreign objects present in the lower part of the vehicle seat 1. As shown in Figure 1, the foreign object detection device 7 is positioned at the lower rear of the vehicle seat 1, for example, on the seat back 4 side of the center of the seat cushion 3 in the front-to-back direction, and is positioned diagonally downward on the vertically lower side of the seat cushion 3. The foreign object detection device 7 may also be positioned vertically downward. In the following description, the foreign object detection device 7 will be described assuming it is positioned vertically downward. In this embodiment, the foreign object detection device 7 is attached to the connecting rod 13 at the rear of the seat and is positioned outside the seat cushion 3.

[0017] Here, the foreign object refers to, for example, the feet of the occupant in the rear seat as shown in FIG. 1, or work boots placed on the floor. Also, the lower part of the vehicle seat 1 refers to the space between the vehicle seat 1 and the floor surface 30 of the vehicle. For example, in an electric vehicle, since a battery pack or the like is arranged below the floor surface 30, the floor surface 30 tends to be higher compared to a vehicle that does not require a battery pack or the like. As a result, the space between the vehicle seat 1 and the floor surface 30 of the vehicle becomes narrower compared to a vehicle that does not require a battery pack or the like. Therefore, it is required to be able to appropriately detect foreign objects.

[0018] The foreign object detection device 7 includes a pressure sensor 21, a pressure sensor mounting plate 23, a stopper 25, and a pressing plate 27. The foreign object detection device 7 may further include a cushion material 29. The pressure sensor 21 is a sensor that detects a pressing force. The method for detecting the pressing force by the pressure sensor 21 is not particularly limited as long as it can detect the pressing force by a foreign object. In the present embodiment, a membrane-type pressure sensor 21A is used.

[0019] The pressure sensor mounting plate 23 is a plate-shaped member extending in the seat width direction. The longitudinal direction of the pressure sensor mounting plate 23 is set to coincide with the seat width direction. The length of the pressure sensor mounting plate 23 in the seat width direction is substantially the same as the length of the seat cushion 3 in the seat width direction. The pressure sensor mounting plate 23 has a connecting portion 23A shown in FIG. 2 and two through holes 23B shown in FIG. 3. The connecting portion 23A is a part for connecting the pressure sensor mounting plate 23 to the vehicle seat 1. The connecting portion 23A of the present embodiment is a hook-shaped part. The through holes 23B are holes provided at both ends of the pressure sensor mounting plate 23 in the seat width direction. The pressure sensor mounting plate 23 is arranged along the connecting rod 13 at the rear of the seat and is connected to the connecting rod 13 by hooking the connecting portion 23A on the connecting rod 13.

[0020] At least one pressure sensor 21A is mounted on the pressure sensor mounting plate 23. In this embodiment, four pressure sensors 21A are provided. Therefore, the four pressure sensors 21A are mounted on the pressure sensor mounting plate 23 in a row in the sheet width direction. The pressure sensors 21A are mounted on one surface of the pressure sensor mounting plate 23 facing downwards from the sheet.

[0021] The stopper 25 is a part that suppresses deformation of the pressure sensor 21 in the pressing direction. The stopper 25 is a part that protrudes from the surface of the pressure sensor mounting plate 23 on which the pressure sensor 21 is mounted toward the thickness direction of the pressure sensor 21. The length of the stopper 25 in the pressing direction of the pressure sensor 21 is shorter than the distance between the pressure sensor mounting plate 23 and the pressing plate 27 (described later) when the pressure sensor 21 detects the pressing force from a foreign object. In other words, the height (i.e., the amount of protrusion) of the stopper 25 is set so that the stopper 25 does not obstruct the detection of the pressing force.

[0022] The stopper 25 is positioned along the outer circumference of the pressure sensor 21. In this embodiment, the pressure sensor 21 is cylindrical, and the stopper 25 is positioned intermittently so as to surround a portion of the periphery of the pressure sensor 21. Alternatively, the stopper 25 may be positioned continuously so as to surround the entire periphery of the pressure sensor 21.

[0023] The pressing plate 27 is a plate-shaped member that extends in the width direction of the sheet. The pressing plate 27 is positioned opposite the surface of the pressure sensor mounting plate 23 to which the pressure sensor 21 is attached. The pressing plate 27 is positioned vertically below the pressure sensor mounting plate 23. As shown in Figure 3, the pressing plate 27 has two insertion parts 27A. The insertion parts 27A are cylindrical portions that are inserted through the through holes 23B of the pressure sensor mounting plate 23. The ends of the insertion parts 27A are configured to prevent them from falling out of the through holes 23B. For example, the ends of the insertion parts 27A are configured to be larger than the through holes 23B.

[0024] In this configuration, when subjected to external pressure, the insertion portion 27A and the through hole 23B can slide, and the pressing plate 27 slides relative to the pressure sensor mounting plate 23. That is, the pressing plate 27 can press the pressure sensor 21 by moving closer to and further away from the pressure sensor mounting plate 23 in response to the pressure from foreign objects.

[0025] The cushioning material 29 is an elastic member for transmitting the pressing force from the pressing plate 27 to the pressure sensor 21. For example, urethane can be used for the cushioning material 29. The cushioning material 29 is placed in the space between the pressure sensor mounting plate 23 and the pressing plate 27. The pressure sensor 21A is attached to the cushioning material 29. The side of the cushioning material 29 opposite to the side to which the pressure sensor 21A is attached is attached to the pressing plate 27. The length (i.e., thickness) of the cushioning material 29 in the pressing direction (i.e., vertical direction) of the pressure sensor 21 is greater than the length of the stopper 25 in the pressing direction.

[0026] The movement of the foreign object detection device 7 when the vehicle seat 1 is displaced downwards while a foreign object is present beneath the vehicle seat 1 will be explained using Figure 4. Before the vehicle seat 1 is displaced downwards, the pressure sensor 21A and cushioning material 29 are not deformed, and the stopper 25 and pressing plate 27 of the pressure sensor mounting plate 23 are separated. In Figure 4, the state in which the cushioning material 29 is in contact with the pressing plate 27 before the vehicle seat 1 is displaced downwards is illustrated, but the cushioning material 29 may be separated from the pressing plate 27.

[0027] As the vehicle seat 1 begins to move downward, the pressure plate 27 comes into contact with the foreign object. As the vehicle seat 1 continues to move, the pressure plate 27 is slidable relative to the pressure sensor mounting plate 23, and therefore receives pressure from the foreign object and slides closer to the pressure sensor mounting plate 23. Because the pressure plate 27 is in contact with the elastic cushioning material 29, as the pressure plate 27 slides closer to the pressure sensor mounting plate 23, the cushioning material 29 is compressed in the direction of pressure applied by the pressure sensor 21A. The pressure sensor 21A is pressed by the restoring force of the cushioning material 29, causing two electrodes (not shown) located inside to come into contact and detect the pressure from the foreign object located at the lower rear of the vehicle seat 1. At this point, the vehicle seat 1 stops moving downward and, for example, reverses direction and moves upward.

[0028] When the vehicle seat 1 is displaced upward while the cushioning material 29 is compressed in the direction of pressure sensor 21A, the cushioning material 29 returns to its pre-compression state, pressing the pressure plate 27 downward due to its restoring force. The pressure sensor 21A is no longer pressed by the restoring force of the cushioning material 29, and the detection of pressure from foreign objects ends.

[0029] On the other hand, when the vehicle seat 1 is not moving, foreign objects may get trapped underneath the vehicle seat 1. In vehicles such as electric vehicles where the space between the vehicle seat 1 and the vehicle floor 30 is narrow, foreign objects trapped underneath the vehicle seat 1 will press against the pressure plate 27, thereby pressing against the pressure sensor 21A. In this way, if the pressure sensor 21A is pressed when the vehicle is stopped, the vehicle seat 1 will not move upward. As a result, the foreign objects will press against the pressure sensor 21A for a long time, and the pressure sensor 21A may remain in a deformed state.

[0030] However, a stopper 25 is positioned on the pressure sensor mounting plate 23 along the outer circumference of the pressure sensor 21A. The stopper 25 is set to a height that does not obstruct the detection of the pressing force by the pressure sensor 21A, and suppresses excessive movement of the pressing plate 27. This prevents irreversible deformation of the pressure sensor 21A.

[0031] [1-2. Effects] The first embodiment described in detail above provides the following effects. (1a) The foreign object detection device 7 is located at the rear lower part of the vehicle seat 1. The foreign object detection device 7 includes a pressure sensor 21 and a stopper 25. The pressure sensor 21 detects the pressing force of a foreign object located at the rear lower part of the vehicle seat 1. The stopper 25 suppresses deformation of the pressure sensor 21 in the direction of pressing.

[0032] With this configuration, the stopper 25 suppresses excessive deformation of the pressure sensor 21 in the pressing direction, thereby preventing irreversible deformation of the pressure sensor 21. In particular, even in situations where the pressure sensor 21 is left in high temperatures for a long time, such as inside a car in direct sunlight, and foreign objects such as work shoes are pushed under the seat, causing a sustained pressing force on the pressure sensor 21, irreversible deformation of the pressure sensor 21 can be suppressed.

[0033] (1b) The foreign object detection device 7 further comprises a pressure sensor mounting plate 23 and a pressing plate 27. The pressure sensor mounting plate 23 is a plate-shaped member extending in the width direction of the vehicle seat 1 and to which the pressure sensor 21 is mounted. The pressing plate 27 is a plate-shaped member extending in the width direction of the vehicle seat 1 and can press the pressure sensor 21 by moving closer to and further away from the pressure sensor mounting plate 23 in response to the pressing force of the foreign object. The stopper 25 is configured to protrude from at least one of the pressure sensor mounting plate 23 and the pressing plate 27 in the space between the pressure sensor mounting plate 23 and the pressing plate 27.

[0034] With this configuration, the pressing plate 27 extending in the width direction presses against the pressure sensor 21, so that the pressure sensor 21 can detect foreign objects over a wide area in the width direction without having to arrange the pressure sensor 21 over a wide area in the width direction. In addition, since the stopper 25 is configured to suppress excessive movement of the pressing plate 27, irreversible deformation of the pressure sensor 21 can be suppressed.

[0035] (1c) The stopper 25 is positioned along the outer circumference of the pressure sensor 21. With this configuration, deformation of the pressure sensor 21 can be suppressed more effectively compared to a configuration in which the stopper 25 does not follow the outer circumference of the pressure sensor 21.

[0036] [2. Second Embodiment] [2-1. Differences from the First Embodiment] The second embodiment has the same basic configuration as the first embodiment, so the differences will be explained below. Note that the same reference numerals as in the first embodiment indicate the same components, and refer to the preceding description.

[0037] In the first embodiment described above, a membrane-type pressure sensor 21A is used. In contrast, the second embodiment differs from the first embodiment in that it uses a deformation-detection type pressure sensor 21B.

[0038] The pressure sensor 21B shown in Figure 5 is a columnar sensor extending in the sheet width direction. The length of the pressure sensor 21B in the sheet width direction is approximately the same as the length of the sheet cushion 3 in the sheet width direction. In other words, the pressure sensor 21B is mounted over the entire sheet width direction of the pressure sensor mounting plate 23. The pressure sensor 21B has multiple exposed electrodes arranged inside an elastic outer casing member. The outer casing member of the pressure sensor 21B may be made of, for example, rubber.

[0039] The length of the pressure sensor 21B in the pressing direction is greater than that of the stopper 25. Therefore, the foreign object detection device 7 of the second embodiment does not require a cushioning material 29, and the pressing plate 27 directly presses against the pressure sensor 21B.

[0040] In the second embodiment, the pressing plate 27 is curved toward the pressure sensor mounting plate 23. The front end of the pressing plate 27 is fixed to the pressure sensor mounting plate 23 so as to be rotatable, and the rear end is inserted through the through hole 23B of the pressure sensor mounting plate 23. Therefore, when the pressing plate 27 is subjected to a pressing force from a foreign object, it is displaced upward from the sheet with the front end of the sheet as the axis of rotation.

[0041] Then, the pressure sensor 21A is pressed by the pressing plate 27, causing the multiple electrodes located inside to come into contact with each other, and the pressing force is detected.

[0042] In the second embodiment, the stopper 25 is positioned along the longitudinal direction of the pressure sensor 21B. That is, the stopper 25 is positioned to surround both sides of the pressure sensor 21B in the longitudinal direction (i.e., the front side of the seat and the rear side of the seat). The length of the stopper 25 in the seat width direction is approximately the same as the length of the seat cushion 3 in the seat width direction.

[0043] The movement of the foreign object detection device 7 of the second embodiment when a foreign object is present under the vehicle seat 1 and the vehicle seat 1 is displaced downward will be explained with reference to Figure 6. Before the vehicle seat 1 is displaced downward, the pressure sensor 21B is not deformed, and the stopper 25 and the pressing plate 27 of the pressure sensor mounting plate 23 are separated.

[0044] When the vehicle seat 1 begins to move downward, the pressure plate 27 comes into contact with the foreign object. As the vehicle seat 1 continues to move, the pressure plate 27 is displaceable relative to the pressure sensor mounting plate 23, and therefore receives the pressure from the foreign object and displaces itself to move closer to the pressure sensor mounting plate 23. As the pressure plate 27 displaces itself to move closer to the pressure sensor mounting plate 23, the pressure plate 27 presses against the pressure sensor 21B, and the pressure sensor 21B detects the pressure from the foreign object. At this point, the vehicle seat 1 stops moving downward and reverses direction to move upward.

[0045] When the vehicle seat 1 is displaced upward while the pressure sensor 21B is pressed, the pressure plate 27 ceases to receive pressure from the foreign object, and the detection of pressure from the foreign object ends.

[0046] [2-2. Effects] The second embodiment described in detail above achieves the effect (1a) of the first embodiment described above, and further achieves the following effects.

[0047] (2a) The pressure sensor 21B has a length that is approximately the same as the length of the seat cushion 3 in the seat width direction. With this configuration, the foreign object detection device 7 does not need to be equipped with multiple pressure sensors 21 and can detect the pressing force of a foreign object with a simple configuration.

[0048] [3. Other Embodiments] Although embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0049] (3a) In the above embodiment, the stopper 25 is provided on the pressure sensor mounting plate 23, but is not limited to this. For example, the stopper 25 may be provided on the pressing plate 27. That is, the pressure sensor 21 and the stopper 25 may each be provided on separate members. [Explanation of Symbols]

[0050] 1...Vehicle seat, 3...Seat cushion, 4...Seat back, 5...Cushion frame, 7...Foreign object detection device, 13...Connecting rod, 15...S-shaped spring, 21, 21A, 21B...Pressure sensor, 23...Pressure sensor mounting plate, 23A...Connection part, 23B...Through hole, 25...Stopper, 27...Pressing plate, 27A...Insertion part, 29...Cushioning material, 30...Floor surface.

Claims

1. A foreign object detection device positioned at the rear lower part of a vehicle seat, which detects foreign objects present at the bottom of the vehicle seat, A pressure sensor located at the rear lower part of the vehicle seat detects the pressing force exerted by a foreign object, A stopper that suppresses deformation of the pressure sensor in the pressing direction, A foreign object detection device equipped with the following features.

2. A foreign object detection device according to claim 1, A plate-shaped member extending in the width direction of the vehicle seat, which is a pressure sensor mounting plate to which the pressure sensor is attached, A plate-shaped member extending in the width direction of the vehicle seat, which is a pressing plate capable of pressing the pressure sensor by moving closer to and further away from the pressure sensor mounting plate in response to the pressing force of the foreign object, Furthermore, The stopper is configured to protrude from at least one of the pressure sensor mounting plate and the pressing plate in the space between the pressure sensor mounting plate and the pressing plate. Foreign object detection device.

3. A foreign object detection device according to claim 1 or claim 2, The stopper is positioned along the outer circumference of the pressure sensor. Foreign object detection device.

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